This document provides instructions for creating a scrolling background for a 2D game using Unity. It describes adding a script called CameraFollow to make the camera follow the player character. It then describes adding another script called GeneratorScript to the player character to manage spawning prefab mountains as the character moves to create the illusion of a scrolling background. Key steps include creating a prefab from background assets, and using that prefab and scripts to spawn, track, and remove mountains over time to simulate horizontal scrolling of the background environment.

1. Derived from Kirill Muzykov’s Rocket Mouse Tutorial
http://www.raywenderlich.com/69392/make-game-like-jetpack-joyride-unity-2d-part-1
@shahedC
WakeUpAndCode.com

3. Double-click Cat Controller in Scripts subfolder

4. Type this inside the class before the Start() method

5. Type these 3 lines
inside FixedUpdate()
just before it ends

6. Run
Where
does the
cat go?

8. Right-click Scripts, click Create  C# Script Name it “CameraFollow”

9. Drag
Script to
Main Camera
Verify Script
Component

10. Double-click CameraFollow in Scripts subfolder

11. Type this inside the class before the Start() method

12. Type these 4 lines inside the Update() method before the class ends

13. Target Object: None

14. Drag
Cat to
Camera’s
Target
Object

15. Run
Does the
camera
follow
the cat?

17. Position:
• X = -3.5
• Y = 0
• Z = 0

18. Type this inside the class before the Start() method

19. Type this inside Start() method

20. Add distanceToTarget to newCameraPosition

21. Run
The cat
should
stay to
the left

23. Click “Game Object”  Create Empty Verify Game Object in Hierarchy

24. Rename to “mount1” Set Position: 0, 0, 0

25. Drag
“mountains”,
“floor” and
“ceiling” into
“mount1”
NOTE: you can
also add other
objects that you
may have added
as part of the
background.

26. In Project panel,
right-click
“Assets”
folder
Click Create, then Folder
Name it “Prefabs”

27. Drag
“mount1”
into
“Prefabs”
NOTE: the
“mount1” in the
hierarchy should
turn blue.

29. Right-click Scripts, click Create  C# Script Name it “GeneratorScript”

30. Drag
Script
to Cat
Verify Script
Component

31. Double-click “GenerateScript” in Scripts subfolder

32. Add “using” statement
above the class
Add 3 instance variables
inside the class

33. Add 2 lines of code
inside the Start() method

35. Write AddMountains() method
with these 6 lines of code

36. Create new method, add variables, initialize them

37. Add foreach loop to figure out mountains

38. Add foreach loop to destroy/add mountains

39. Create FixedUpdate() Method, add 1 line of code

41. Select “Cat” in
Hierarchy
Drag “mount1”
to Current Mountains
Under GeneratorScript

42. Select “Cat” in
Hierarchy
Drag “mount1”
PreFab
to Available
Mountains
Under
GeneratorScript

43. Do you have
extra
mountains
in hierarchy?
(not part of
“mount1”)
Remove them!

44. Run
The background
should scroll now!